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Hooke, Robert, 1635-1703 / Micrographia: or some physiological descriptions of minute bodies made by magnifying glasses : with observations and inquiries thereupon
(MDCLXVII [1667])

Observ. X. Of metalline, and other real colours,   pp. 67-79

Page 67

               MICROG R AP 1AA,                                      67
Shall be generated feveral confecutlonm of colours, whofe order from the
thin end towards the thick, fhall be deiowc fled, Purple, BlueGreez 5 Tel/ow'
RedAprpleBlxueGreen; TeIlowRedPurple BlueGreen5 Te/low,&c. and thefe
fo often repeated, as the weaker pull e does lofe paces with its Priazar
or firft pulfe, and is coinrident with a fecond, third, fourthfifthfixth.&C
Fulfe behind the firfi. And this, as it is coincident, or follows from the
firif Ipothefs I took of coloursnfo upon exeriment have I found it in mul-
titudes of infcances that feem to prove it. One thing which feems of the
greateft concern in this Hypothefis, is to determine the greateft or leaff
thickness requifite for there effeds, which, though I have not been want-
ing in attempting, yet fo exceeding thin are thefe coloured Plates, and fo
imperfed our Microfrope~that I have not been hitherto fuccefsfullthough
if my ebdeavours {hall anfiwer my expei'fations,I fhall hope to gratifie
curious Reader with ome things more remov'd beyond our reach
  Thus have Iwith as much brevity as I was able, endeavoured to expli-
cate(Hypothetically at leaft) the caufes of the Pbxhvorena I formerly re-
cited, on the confideration of which I have been the more particular.
  Firit, becaufe I think thefe I have newly given are capable of expli-
cating all the Fhhbnonena of colours, not onely of thofe appearing in the
Fri fine, Water-drop, or Rainbow, and in laminated or plated bodies, but
of all that are in the world, whether they be fluid or folid bodies, whe-
ther in thick or thin, whether tranfparent, or feemingly opacous, as I
thall in the next Obfervation further endeavour to fhew. And fecondly,
becaufe this being one of the two ornaments of all bodies discoverable
by the fight, whether looked on with, or without a Aficrofcope, it feem'd
to deferve (fomewhere in this Trad, which contains a description of the
Figure and Colour of fome minute bodies) to be fomewhat the more in-
tirnately enquir'd into.
       Obferv. X. Of Metalline, and other real Colours.
H  Aving in the former Difcourfe, from the Fundamental caufe of Co-
R I lour, made it probable, that there are but two Colours, and fhewn,
that the Phantafm of Colour is caus'd by the fenfation of the oblique or
uneven pulfe of Light which is capable of no more varieties than two
that arife from the two fides of the oblique pulfe, though each of thofe
be capable of infinite gradations or degrees (each of them beginning
from Wkite, and ending the one in the deepeft scarlet or Tel/ow, the other
in the deepeft Blue) I fiall in this Sedion fet down fome Obfervations
which I have made of other colours, fuch as Ayetabline powders tinging
or colour d bodies and feveral kinds of tirtiures or ting'd liquors, all
which, together with thofe I treated of in the former Obfervation will1
I fuppofe, conmpiife the fveral fubjeds in which colour is obferv'd to
be inherent, and the feveral manners by which it inberei, or is apparent
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